We highlight the importance of combining different approaches: laboratory experiments, computer simulations, and observations. The goal is to better understand how these small bodies evolve, what they're made of, and how they influence space environments.
We especially welcome presentations on recent and upcoming space missions, early career scientists, and cross-disciplinary research and collaborative ideas.
Meteoroid streams and their associated meteor showers provide useful constraints on the small-body and dust environment near Earth, but many weak, high-latitude, and daytime showers are still not well documented. We introduce a framework to use almost two decades of observations from six European VHF meteor radars—Collm (Germany), Tromsø, Alta and Svalbard (Norway), Esrange/Kiruna (Sweden), and Sodankylä (Finland)—to map, track, and classify meteoroid streams in a consistent way. Starting from monostatic echo detections that provide location and velocity information, we combine thousands of individual meteors into daily radiant intensity maps in ecliptic coordinates as a function of solar longitude. For each radar, we then construct composite radiant maps with 1° resolution in solar longitude, yielding 360 maps per composite year. Image-processing methods (background removal, local-maximum detection, and clustering in both (λ, β) and sun-centred (λ−λ⊙, β) coordinates) are applied to automatically identify candidate shower radiants and to follow their motion with solar longitude. A simple tracking algorithm connects radiants between consecutive solar-longitude slices and produces radiant tracks that can be compared with IAU shower lists and video-network solutions for stream identification and preliminary source attribution. In this contribution we will describe the methodology, show initial examples of radiant maps and tracked streams, and discuss how radar-based statistics of meteor radiants from these six stations can be combined with optical observations and meteoroid-stream modelling to improve our picture of the near-Earth meteoroid environment.
How to cite: Lu, M., Stober, G., Yi, W., Xue, X., Kero, J., Kozlovsky, A., Lester, M., Nozawa, S., Tsutsumi, M., Gulbrandson, N., Jacobi, C., and Mitchell, N.: Mapping and tracking meteoroid streams with a 20-year European meteor radar network, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13349, https://doi.org/10.5194/egusphere-egu26-13349, 2026.
Dust particles play an important role in the physics and chemistry of the mesosphere. Nanometer-scaled particles, denoted as meteoric smoke particles (MSPs) and formed on the course of the ablation process of a meteoroid, are one of the most plausible candidates for contributing to forming ice particles by acting as condensation nuclei. Because of measurement difficulties, very little is known about the MSPs composition which is yet of crucial importance to model their charge and radius distribution. Accordingly, the Maxidusty-2 rocket was launched into a noctilucent cloud on 5th July 2025. The success of this campaign enables to perform different in-situ measurement with multiple dust detectors including the collection of dust samples.
Preliminary analysis of the samples using transmission electron microscopy (TEM) at the NTNU TEM Gemini Centre indicates the presence of metals, notably phosphorus and magnesium. Three different types of dust detectors measured signals as the rocket passed through the altitude of the noctilucent cloud.
In this presentation, we will discuss the first results of sample analysis based on the first measurement at the NTNU TEM Gemini Centre and compare them with in-situ measurements. We also address the challenges in the analytical methods associated with these unique samples and present initial findings on the size distribution of nm-scale particles.
How to cite: Yokoyama, Y., Olsen, S. V., Eilertsen, Y., Spicher, A., Tinguely, J.-C., Ludacka, U., Hedin, J., Kimura, Y., Tanaka, K., and Pineau, A.: Mesospheric dust studies with sample analysis and in-situ measurement from Maxidusty-2, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8917, https://doi.org/10.5194/egusphere-egu26-8917, 2026.
The NEO Physical Observations and Properties Simulations (NEOPOPS) project, funded by the European Space Agency (ESA) and led by INAF – OAR (Observatory of Rome) is dedicated to the physical characterization of Near-Earth Objects (NEOs). The study of these objects is essential for several reasons. From a science perspective, NEOs may have played a role in delivering organic material and water to Earth (Morbidelli et al., 2000; Marty et al., 2016), and thus preserve key information about their origin and evolution from the early Solar System. From a planetary defense standpoint, NEOs can also pose a significant threat to Earth. Several events in the Earth’s history (K-Pg impact, the Chelyabinsk fall in 2013 and more recently the alert triggered by 2024 YR4 in early 2025) demonstrate that this population can cause substantial material damage and, in extreme cases, mass extinctions.
To mitigate the risk posed by potentially hazardous objects, it is crucial to characterize them shortly after their discovery. The NEOPOPS project therefore conducts spectroscopic, photometric, and polarimetric observations using multiple telescopes, including the 3.58m TNG (La Palma, Spain), the 8.2m VLT (Cerro Paranal, Chile), the 1.54m Danish telescope (La Silla, Chile) and the 1.82m Copernico Telescopio (Asiago, Italy). Our goal is to constrain key physical parameters that may inform potential mitigation strategies in the event of a future impact threat.
This presentation focuses on the characterization of NEOs by spectroscopy, photometry, polarimetry and rapid response. We aim to obtain monthly observations of NEOs selected according to three prioritized criteria: (1) objects that pose a potential impact risk, identified in collaboration with the NEO Coordination Center (NEOCC, ESA-ESRIN), which issues alerts when a threat is detected; (2) NEOs that are targets of upcoming space missions; and (3) recently discovered NEOs, which are particularly challenging to observe because their visibility window may last only few weeks, after which they can remain unobservable for decades. The spectra obtained provide constraints on surface composition, possible surface heterogeneity, and other physical properties, and are shared across NEOPOPS observer team to enable a comprehensive characterization of each object.
For the rapid-response observations, the goal is to provide rapid, multi-technique observations to derive critical parameters relevant to impact mitigation planning. In the event of an alert, all the observing teams are mobilized to observe the object as quickly as possible. Triggered-alert objects may become unobservable shortly after discovery, often well before their predicted virtual impact date. In 2025, four alerts were issued, 2024 YR4, 2025 FA22, 2025 SC5, and 2025 VP2, with Torino Scale (Binzel et al., 2000) values ranging from 1 to 3. These real-case scenarios allowed us to test and validate our rapid response procedures and to derive key parameters, such as albedo, rotational period estimates, and surface composition.
How to cite: Bourdelle de Micas, J., Ieva, S., Dotto, E., Pravec, P., Lazzarin, M., Farina, A., Bagnulo, S., Perna, D., Mazzotta Epifani, E., Barucci, A., Ferri, F., La Forgia, F., Mura, A., Fatka, P., and Devogèle, M.: NEOPOPS – Ground based observations in support of the planetary defense, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8011, https://doi.org/10.5194/egusphere-egu26-8011, 2026.
Introduction: The bright deposits of Cerealia Facula within Occator Crater on Ceres are key indicators of recent endogenic activity, most likely linked to cryovolcanic and hydrothermal processes and the presence of subsurface brines. Constraining the absolute model age of these deposits is essential for understanding the geologic evolution of Occator and the thermal history of Ceres. Previous crater size–frequency distribution (CSFD) studies suggested Cerealia Facula is significantly younger than the Occator impact, but these were limited by small counting areas, low crater statistics, and challenges in crater detection due to complex geomorphology and significant albedo variations. The Dawn mission’s seventh, final Extended Mission Orbit (XMO7) provided the highest-resolution images of Occator, but their full scientific potential required accurate co-registration and orthorectification.
Objectives and Data: This work presents (1) a statistically robust model age for Cerealia Facula based on improved CSFD measurements, and (2) a suite of high-resolution, co-registered geospatial data products publicly available via Zenodo (doi: 10.5281/zenodo.17615400, doi: 10.5281/zenodo.14531595). Our analysis uses Dawn Framing Camera data from multiple mission phases, including XMO7 (resolutions down to ~2.7 m) and LAMO (~34 m). We combined LAMO multispectral RGB data with XMO7 clear-filter imagery, incorporating data from both FC1 and FC2 cameras to maximize spatial coverage. The resulting orthomosaics, including a pan-sharpened RGB product at 8.5 m ground sample distance, provide unprecedented spatial and spectral detail.
Methodology: Accurate image co-registration and orthorectification were achieved using a hierarchical approach, anchoring XMO7 data to a stable geodetic reference frame based on a high-resolution DTM we published early 2025. CSFD measurements were conducted across the entire facula, focusing on craters >50 m to minimize detection bias. Independent counts by multiple analysts assessed variability and robustness. Model ages were derived using both lunar-derived and asteroid-flux-derived chronology models.
Results and Implications: The new orthomosaics and DTM reveal a surface more complex than previously observed, with steep slopes, fractures, and albedo variations complicating crater identification. CSFD results confirm Cerealia Facula postdates the Occator impact, with model ages ranging from 0.4 to 39.5 Ma (most likely in the single-digit Ma range), depending on used scaling parameters during the modelling of the chronology models. These findings are supported by improved statistics and reduced detection variability. Beyond age determination, the principal outcome is the creation of a high-resolution, controlled, publicly accessible geospatial dataset (clear-filter-, pan-sharpened RGB orthomosaic and DTM) for Occator Crater, enabling future studies of cryovolcanic processes and surface modification. Furthermore, the published datasets will allow to perform detailed studies and assessments of potential future landing sites
Conclusion: This work advances our understanding of Ceres’ recent geologic activity and provides a critical baseline for future investigations, extending the scientific legacy of the Dawn mission.
How to cite: Neesemann, A., van Gasselt, S., and Riedel, C.: Revisiting the crater-based age of Cerealia Facula: High-resolution XMO7 data, measurement uncertainties, and chronological frameworks , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22111, https://doi.org/10.5194/egusphere-egu26-22111, 2026.
Despite extensive study, the origin of the Martian moon Phobos remains still an unresolved question. Linking its orbital configuration, spectral features and geodetic observables to one formation mechanism remains a challenging task. Determining and understanding Phobos’s gravitational field is a fundamental step toward constraining its interior and, consequently, its origin. Current estimates suggest a porous interior with possible water-ice content and a denser mass concentration in its equatorial region.
This study investigates Phobos’s geophysical observables under different impact scenarios at the Stickney crater to assess whether such events could account for the observed offset in its degree-two gravity coefficients relative to the homogeneous case. We model two impact geometries, representing different mass distributions along Stickney and assume that the impact produced one of two types of molten rock, each tested for three volume fractions. Each scenario is tested on layered, rubble-pile and Perlin-Noise-based interior, with and without impact. All interiors contain the same volume of water-ice and porosities, and we normalize the mass of its rocky component to conserve Phobos total mass.
Our results indicate that if Phobos is a based on one of the proposed interior, the offset in the degree-two coefficients is caused by the compressed mass beneath Stickney. This provides a more straightforward explanation than the suggestion that Phobos consists of a light core and dense crust.
How to cite: Haser, B. and Andert, T.: How the mass beneath Stickney affects Phobos geophysical properties, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1864, https://doi.org/10.5194/egusphere-egu26-1864, 2026.
The origin of Phobos and Deimos remains uncertain. Most active hypotheses for the formation of Mars’s small moons fall into two categories: direct capture and a giant impact. The moons’ spectral oddities suggest that they might be asteroids caught by the planet. However, their near-circular and near-equatorial orbits more naturally align with accretion from a disk around Mars, typically assumed to have arisen from a large impact. Distinguishing between these two scenarios is the primary goal of the imminent JAXA Martian Moons eXploration (MMX) mission.
We present a new alternative scenario wherein fragments of a tidally disrupted asteroid are captured and evolve into a collisional proto-satellite disk. We model both the initial disruption and the fragments’ subsequent evolution, using a combination of high-resolution smoothed particle hydrodynamics (SPH) simulations and orbit integrations.
We find that tens of percent of an unbound asteroid’s mass can be captured and survive beyond collisional timescales, across a broad range of periapsis distances, speeds, masses, spins, and orientations in the Sun–Mars frame. Furthermore, more than one percent of the asteroid’s mass could evolve to circularise in the moons’ accretion region in the outer disk, compared with a far lower fraction for a post-impact disk. The resulting lower mass requirement for the parent body than that for a giant impact could open up a greater population of potential parents in the early Solar System, contributing to a higher likelihood route to forming a proto-satellite disk that, unlike direct capture, could also naturally explain the moons’ orbits.
The satellites that would arise from this new scenario of disruptive partial capture or from each of the two established origin hypotheses would have different bulk compositions, volatile contents, and other properties that will soon be tested by MMX to constrain the origin of Mars’s moons.
How to cite: Kegerreis, J., Lissauer, J., Eke, V., Sandnes, T., and Elphic, R.: Origin of Mars’s moons by disruptive partial capture of an asteroid, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15016, https://doi.org/10.5194/egusphere-egu26-15016, 2026.
The complex makeup of interplanetary dust undergoes a continuous cycle of production, transport, and diminishment through various physical processes. The zodiacal cloud, a vast structure within the Solar System originating from particles released by comets and asteroids, undergoes erosion through collisional grinding, fragmentation, sputtering, and sublimation when it is near the Sun. The primary driver of the inner zodiacal cloud evolution is collisional erosion; however, collision rates and the associated fragmentation in the most frequent collision areas have not been well quantified. Solar Orbiter (SolO) is gradually increasing its inclination, enabling measurements to be taken beyond the ecliptic plane (~17° latitude in 2025-2026). This latitudinal tilt allows SolO to sample regions above and below the ecliptic plane. Our work aims to provide two scientific insights through a comprehensive data-model comparison: (1) What are the spatial and temporal variabilities of the inner heliospheric dust environment? (2) To what extent does collisional fragmentation contribute to the mass loss of the zodiacal cloud with latitudinal dependence?
How to cite: Shen, M., Malaspina, D., Píša, D., Pokorný, P., Szalay, J., Souček, J., Zaslavsky, A., Maksimovic, M., and Bale, S.: Out-of-the-Ecliptic Dust Investigation via Solar Orbiter RPW Observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1395, https://doi.org/10.5194/egusphere-egu26-1395, 2026.
Saturn’s narrow, clumpy F ring is in a region disturbed by chaotic orbital dynamics. The ring appears dominated by dust in camera images, but the main mass of this ring resides in a core of elongated clumps called kittens, observed by Cassini UVIS and RSS ring occultations. Approximating this chaos as a random process, I model the F ring core as a finite Markov chain of transient aggregates [20m < dr < 3 km]. The model includes perturbations due to Prometheus encounters, resonance confinement, and mutual collisions. The best description for the current ring is the stationary state of this stochastic process. In this model, the persistence of the F ring is due to negative diffusion [described by Sickafoose and Lewis 2024, to explain the persistence of Chariklo’s rings], where the ring is confined by Prometheus aligning particles when they are driven to collide when their streamlines cross. The F ring is thus shepherded by a combination of a Prometheus corotation and a Lindblad resonance. Whenever the center of mass of the material in the F ring is located at the Lindblad resonance with Prometheus, perturbations will drive negative diffusion to maintain that location. Likewise, negative diffusion can maintain apse alignment and thus ring eccentricity. If the F ring originated from the destruction of a small moon on an elliptical orbit, negative diffusion preserves the original orbital elements of the moon against differential precession and collisional spreading.
The stages in F ring history are as follows. A progenitor moon, say ‘Festus’, accretes from viscous spreading of Saturn’s rings material that crosses the Roche limit. Later, Prometheus accretes. Prometheus, being larger, moves out faster, with a tidal evolution time scale of 10-100 million years… and captures Festus in a mean motion resonance. After that, the two evolve together with the exact resonance evolving chaotically with Prometheus own history of jumps and glitches. If Festus is thus ever out of resonance it is soon re-captured. The mean motion resonance excites Festus eccentricity. Festus (in an eccentric orbit, caught in or near resonance) is shattered by an impact (the estimated lifetime is of the order of 100 million years); the debris mass would be dominated the largest objects (kittens); they would experience anisotropic collisions at streamline crossing that would maintain the moon’s original [a, e, φ] via the negative diffusion. Fragments trapped in nearby resonances have lower optical depth, negative diffusion is weaker and the fragments gradually diffuse away; or they leak into capture within the resonance site with the most original mass. The evaporation of ring material where regular diffusion dominates leaves behind the confined eccentric F ring. Caught in resonance with Prometheus, it will evolve further from Saturn and may eventually re-accrete into a small moon like Anthe.
How to cite: Esposito, L. W.: Origin and Evolution of Saturn’s F Ring with Negative Diffusion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14925, https://doi.org/10.5194/egusphere-egu26-14925, 2026.
Oort cloud comet C/2025 K1 (hereafter K1) was discovered in 2025 May [1] and was observed to fragment on 2025 November 10, when it was ~1 au from the Sun [2,3]. Multiple fragments have been observed since its fragmentation [4, 5], denoted as K1, K1-B, and K1-C, were observed to be located 6 arcsec apart and 13 arcsec apart in mid-November 2025 [6]. A fourth fragment, called D, was observed in late November-early December [7,8]. Additionally, the comet is depleted in carbon-chain molecules such as C2 and CN [9]. Thus, the comet provides an ideal test of volatile heterogeneity within fragments of a recently disrupted comet, which may indicate the extent to which its parent body underwent differentiation through various evolutionary processes in the TND [10,11]. We present JWST observations taken in late 2025 December/early 2026 January when the comet was ~2 au from the Sun, well inside the H2O and CO2 ice lines. We observed the comet during multiple epochs using the NIRCam, MIRI, and NIRspec instruments covering wavelengths 0.7-18 microns. We present imaging and spectroscopy of the comet and its fragments. Our observations indicate multiple epochs of fragmentation that persist as the comet leaves perihelion. We will discuss the physical properties of the fragments, constraints on their volatile contents, and the potential for volatile heterogeneity in the comet.
References:
[1] Denneau et al. 2025, MPEC, K110, [2] Noonan et al. 2025, ATel, 17488, [3] Hale et al. 2025, MPEC, K110, [4] Kostov et al 2025, ATel,17495, [5] Guzik et al 2025, ATel, 17501, [6] Serra-Ricart et al. 2025, ATel 17487, [7] Romanov et al. 2025, MPEC X108, [8] Bolin et al. 2025, ATel, 17529, [9] Ganesh et al. 2025, ATel, 17500, [10] Bottke et al. 2023, PSJ, 4, 9, 168, 42 pp., [11] Prialnik et al. 2008, SSR, 138, 147-164
How to cite: Bolin, B., Kolokolova, L., Ivanova, O., Wong, I., Belyakov, M., and Abron, L.-M.: JWST characterization of fragmenting Oort cloud comet C/2025 K1 ATLAS, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2539, https://doi.org/10.5194/egusphere-egu26-2539, 2026.
The DESTINY+ is a mission led by JAXA which will launch in 2028. Its main destination is the small body Phaethon, and a fast flyby two years after launch will allow for a sensitive detection of submicron ejecta from its surface in order to study its surface composition. The mission will also look for any surface activity. Furthermore, the interplanetary and interstellar dust background is continuously monitored by the Destiny Dust Analyser DDA with high sensitivity. The dust analyser has a sensitive area of 0.03 m2 and uses charge sensing grids and impact ionisation combined with a time-of-flight mass spectrometer. A two-axis pointing platform allows for dust RAM tracking of different dust populations. The reflectron-based spectrometer has demonstrated a mass resolution greater than 100, recording positive ions from an individual particle impact. Organic molecule clusters can be analysed up to masses as high as 1000 amu. Sensitive charge sensing grids provide trajectory information even of submicron grains.
The Flight Unit of DDA was built and qualified. Functional tests at the Stuttgart dust accelerator facility demonstrate the performance of the instrument in mass resolution and dynamic range. The instrument has a mass of 12 kg and a power consumption of 25 W. The instrument is funded by the German Space Agency DLR, and it was developed at the University of Stuttgart with major contributions by the company von Hoerner & Sulger GmbH.
How to cite: Srama, R., Tomoko, A., Henselowsky, C., Kimura, H., Kobayashi, M., Khawaja, N., Krüger, H., Simolka, J., Strack, H., Sterken, V., and Wagner, C.: The Dust Analyser for DESTINY+ : Development Status and Performance, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21692, https://doi.org/10.5194/egusphere-egu26-21692, 2026.
Silica dust particles are naturally present in dusty environments such as interstellar clouds, protoplanetary disks and comets. Quantum dots in form of nanometer-scale semiconductor crystals can be formed on surfaces of these dust particles due to supernova explosions, shock waves, low-temperature condensation or cosmic radiation alteration. An abnormal extended red emission with a color shift dependent on the size of the dust particles in dominant UV light regions are usually observed by astronomers for nebulas or interstellar clouds.
In this study, we present a laboratory investigation of the light re-emission by 6.5 nm CdSe/ZnS core-shell quantum dots present on the surface of micrometer-sized silica dust particle. The dust particle captured in an electrodynamic trap is irradiated by a blue laser at a specific wavelength of 405 nm. The re-emitted light produced by quantum dots with main wavelength of 650 nm is collected by optical lens attached to the trap and guided by optical fiber to wavelength spectrometer. The macroscopic charge of the dust particle is determined from its motion in the trap. This charge can be controlled by 1 keV protons within a range of up to 6 C/kg.
Initial tests indicate that the measured spectrum of the emitted light shifts towards the red end of spectra as the amount of charge on the surface of grain increases.
How to cite: Nouzak, L., Albert, K., Pavlu, J., Pustylnik, M., Wild, J., Safrankova, J., and Nemecek, Z.: Quantum dots coated dust as a main source of molecular clouds abnormal reddening?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7991, https://doi.org/10.5194/egusphere-egu26-7991, 2026.
Researching cosmic dust requires terrestrial facilities for accelerating analogues of different sizes and masses. To address the area of very lightweight particles, electrostatic accelerators like Van-de-Graaf accelerators or Linear Accelerators (LINACs) have proven adequate. A new variable frequency switched 6-stage LINAC of 120 kilovolts (kV) potential was built at the Institute of Space Systems, University of Stuttgart. It utilizes negative voltages, no storage-capacitors, isometric drift tubes, one semiconductor-based high-voltage switch per stage and there is no voltage drop during acceleration. The electronics limit the particle rate at 33 particles per second. By setting a target speed window, the control software and circuitry autonomously chooses the right amount of acceleration-stages to meet that requirement, if possible. Micron-sized iron particles were accelerated successfully achieving speed increase rates of up to 3-times the pre-LINAC speed and a total speed of up to 1300 meters per second (m/s). This platform provides a new tool for dust sensor calibration, impact physics and material surface processing due to its ability to bring particles of different charge-to-mass ratios to a defined target speed. To further increase the speed, mass and ratio of accelerated microparticles, a new setup is under construction. It will utilize 20 stages with up to 25 kV potential each, resulting in a total acceleration potential of 500 kV. The theoretically achievable particle rate for particles between 500 m/s and 2 km/s will be 1000 particles per second.
How to cite: Li, Y., Bauer, M., Srama, R., Behrens, F., Schäfer, F., Mocker, A., Simolka, J., and Strack, H.: Small Linear Accelerators for Charged Microparticles, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7205, https://doi.org/10.5194/egusphere-egu26-7205, 2026.
This research explores the concept of a spectroscopic study deriving a comparative analysis between seven non meteorites and two meteorites such as analysing a Martian, Moon and asteroid meteorites, volcanic rocks and other samples. The goal of this research is to understand differences/similarities between different Space/Earth rock samples and determine whether reflectance spectroscopy method is sustainable to identify terrestrial and extraterrestrial origin rocks. Meteorite samples were provided by Meteorite Museum - Meteoriti.LV. Some of the terrestrial origin samples were provided by authors of the paper, additional data about terrestrial rocks from the ROMA database was used to account for larger quantities of meteorite samples. The main method of data gathering was reflectance spectroscopy in infrared-ultraviolet spectra in the range of 178-880nm. To perform reflectance spectroscopy spectra measurements Ocean Optics USB4000 spectrometer, in the interval of 400-880nm to reduce noise, were used. Measurements were performed on the surface of the samples, and additionally on the points of interest, using sunlight as reflectance light, however, an additional light source was introduced to minimise noise in the IR region. Data was analysed using Python script with matplotlib and pandas libraries. Analysed data was summarized in four graphs with the x axis representing wavelengths in nanometers and y axis reflectance in percentages. Preliminary results reveal observable spectral distinctions between the Earth samples and their Martian, Lunar and meteorite counterparts. Similarities such as curvature and structure of graphs are seen in the same classification samples of meteorites. Furthermore, some of the samples had peaks in the IR region, meaning, presence of organic matter in their composition. This comparative methodology strongly affirms the effectiveness of field-based spectroscopy as a powerful tool for rapidly identifying diagnostic mineral signatures. The resulting findings contribute significantly to broader planetary science objectives by supporting the remote detection and reliable classification of extraterrestrial rocks.
How to cite: Gutniks, D., Karavackis, E., Bērziņš, K., Tekutis, H., Dabas, A., Čakss, M., and Foing, B.: Spectroscopic Characterization of Terrestrial Rocksand Meteorites, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1208, https://doi.org/10.5194/egusphere-egu26-1208, 2026.
Every day, ∼104 kg of planetary and interplanetary material ablates in Earth’s atmosphere, producing meteor trails and depositing metal atoms, ions, and meteoric smoke particles that influence the chemistry and dynamics of the mesosphere–lower thermosphere (MLT) region (80–105 km altitude). These meteoric inputs are linked to interesting phenomena, including noctilucent (polar mesospheric) clouds, polar mesospheric summer echoes (PMSE), and ozone perturbations.
In this work, we present volumetric reconstructions of meteor-trail emissions using a regularized, tomography-like inversion applied to multi-station optical observations. The method follows a parameterized forward-model framework previously developed for auroral tomography. The reconstructions are based on simultaneous observations from up to six stations of the ALIS-4D camera network, employing narrow-band filters centered at 427.8 nm, 557.7 nm, and 670.0 nm.
To our knowledge, this represents the first application of multi-filter optical tomography to meteoric trails. The resulting three-dimensional emission distributions provide new constraints for meteor ablation simulations and a quantitative reference for studies of excitation, transport, and trail evolution during meteoric events.
How to cite: Kvammen, A., Mann, I., Gustasson, B., Brändström, U., Sergienko, T., Kero, J., Huyghebaert, D., Yokoyama, Y., and Løkkeandrea.d.lokke@uit.no, A.: The Volumetric Emission Structure of Meteor Trails, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14182, https://doi.org/10.5194/egusphere-egu26-14182, 2026.
Advancing Small-Body Detection and Spectral Classification with Wide-Field Schmidt Imaging and Synthetic Tracking at Baldone Observatory
- Zariņš, E. Dovgaļuka, M. Kogane, J. Blahins, V. Silamiķelis, I. Eglītis, K. Nagainis
Asteroids hold a dual significance for modern astronomy and planetary science. On one hand, near Earth asteroids (NEAs) pose a measurable impact hazard that requires continuous monitoring, orbit refinement, and early detection to mitigate potential threats to Earth. On the other hand, small bodies are increasingly recognized as reservoirs of metals, water, and rare-earth elements, making them attractive targets for industrial utilization and in-situ resource extraction. Reliable physical and orbital characterization is therefore essential not only for planetary defense but also for understanding the evolutionary processes of the Solar System and supporting future space-resource strategies.
Baldone Observatory (MPC code 069) operates with the 1.2-m class Schmidt telescope, used historically for wide-field photographic surveys and now adapted for CCD-based astrometry, photometry, and slitless spectroscopy. Many asteroid discoveries and a substantial number of astrometric follow-ups have been made using this instrument and its archival plate collection.
The telescope’s optical system features an 0.83-m entrance aperture and an approximately 2.5-m focal length (f/3). The wide field of view makes it particularly well suited to survey work and small-body detection. Additionally, the telescope can be equipped with a 4-degree objective prism, enabling slitless spectral dispersal across the entire field and allowing simultaneous low-resolution spectroscopy of multiple objects.
To improve faint-object detection, especially for fast-moving NEAs, Baldone Observatory conducted initial tests of the Tycho Tracker software suite, which implements modern synthetic tracking algorithms. Unlike traditional long exposures - where moving objects appear smeared - synthetic tracking aligns and stacks sequences of short images along trial motion vectors. This process suppresses sky noise, preserves the signal of moving targets, and effectively increases limiting magnitude.
Test sequences obtained with the Schmidt telescope demonstrate that synthetic tracking enables reliable identification of moving objects fainter than magnitude 21, surpassing the conventional detection threshold previously achievable at Baldone. These results show that synthetic tracking, combined with the telescope’s wide-field capability, meaningfully enhances the observatory’s contribution to NEA surveys and faint object astrometry.
In addition to detection efforts, we obtained a slitless spectrum of the main-belt asteroid (471) Papagena using the Schmidt telescope equipped with the 4° objective prism. Although originally optimised for stellar spectroscopy, the system proved sufficiently sensitive for bright asteroid targets. The resulting reflectance spectrum, after extraction and calibration, agrees well with published datasets and aligns with the Bus-DeMeo taxonomic classification for Papagena. This confirms that objective-prism spectroscopy is feasible for asteroid mineralogical studies at Baldone and suggests a pathway for expanding the observatory’s role in spectral classification.
The combined success of synthetic tracking and slitless spectroscopy demonstrates that the Baldone Schmidt telescope remains a competitive wide-field instrument for asteroid research. Future improvements in detector sensitivity, spectral calibration, and automation of data pipelines are expected to enhance both the depth and the scientific value of observations conducted at MPC 069.
How to cite: Zarins, A.: Advancing Small-Body Detection and Spectral Classification with Wide-Field Schmidt Imaging and Synthetic Tracking at Baldone Observatory, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1251, https://doi.org/10.5194/egusphere-egu26-1251, 2026.
Iron meteorites provide key constraints on early Solar System differentiation and core formation processes [1, and refs. therein]. They furthermore convey insights into genetic relationships and accretionary environments of their parent bodies inferred from oxygen [2] and nucleosynthetic isotope anomalies [e.g., 3,4]. The hitherto ungrouped iron meteorite Washington County is particularly unique, as it is, so far, the only known specimen hosting volume-correlated, solar-wind derived He and Ne within its metal [5], implying an intense solar irradiation history preceding its formation. Despite the significance of Washington County, a genetic link with other meteorite groups as well as an association with non-carbonaceous (NC) or carbonaceous (CC) meteorites remain ambiguous.
Here, we report the discovery of previously undocumented chromite inclusions of ≤13 µm in size, occurring as isolated, angular to subangular grains, which are erratically distributed throughout the metal of Washington County, and use their chemical and oxygen isotopic signatures to trace its origin. Combined SEM–EDS, micro-Raman spectroscopy and electron microprobe analyses identify the mineral inclusions as Mn-bearing chromites (FeCr₂O₄) and manganochromites ((Mn,Fe)(Cr,V)₂O₄), with MnO contents reaching up to ~27 wt%, representing the most Mn-rich natural chromites reported to date. Secondary Ion Mass Spectrometry (SIMS) of 15 chromite inclusions, which are separated by only a few millimeters, reveal a huge δ¹⁸O spread with values ranging from –3.52‰ to +20.38‰, defining an isotopic variability unprecedented among differentiated meteorites. Despite this extreme mass-dependent isotope fractionation, the mean Δ¹⁷O of -0.07 ± 0.13‰ (2σ) tallies with the terrestrial fractionation line (TFL) and overlaps with enstatite chondrites, aubrites and other NC meteorites. The oxygen isotopic data appear uncorrelated with the chromite chemistry ruling out analytical artifacts and instead indicate kinetic isotope fractionation during oxygen diffusion associated with solid-state exsolution of chromite from cooling Fe–Ni metal.
Comparative oxygen isotope systematics of NC and CC iron meteorites [2,3,4] strongly support classification of Washington County as non-carbonaceous iron and infer a common formation region in the inner Solar System. Together with literature evidence for solar-type noble gases in several other NC iron meteorites [5], our results suggest that incorporation of solar signatures into metallic cores preferentially occurred in NC parent bodies, placing new constraints on early Solar System accretion and core segregation.
[1] Scott, E.R.D. (2020), Iron Meteorites: Composition, Age, and Origin, Oxford University Press, 75 pp. [2] Clayton, R.N. and Mayeda, T.K. (1996), Geochim. Cosmochim. Ac. 60, 1999-2017. [3] Worsham, E.A. et al. (2019), Earth Planet. Sci. Lett. 521, 103-112. [4] Kleine, T. et al. (2020), Space Sci. Rev. 216, 55. [5] Vogt, M. et al. (2021), Commun. Earth Environ. 2, 92.
How to cite: Vogt, M., Mahr, D., Ludwig, T., Pack, A., and Trieloff, M.: Oxygen isotope and chemical composition of chromites in the unique iron meteorite Washington County constrain derivation from the inner Solar System non-carbonaceous (NC) reservoir, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6559, https://doi.org/10.5194/egusphere-egu26-6559, 2026.
The Next Generation small-body Sample Return (NGSR) mission is under study for a Japanese strategic large-class science mission in the 2030s. Following Hayabusa, Hayabusa2, and upcoming Martian Moons eXploration (MMX), NGSR aims to return samples from a Solar System primitive body. The samples returned by Hayabsua2 from the C-type asteroid Ryugu indicated the evolution process from its parent body and the transport of materials in the early Solar System [1]. However, the ultimate origin of the Solar System material and the formation of the first-generation planetesimals still remain unsolved. Thus, the science goals of NGSR include (1) unveiling the origin of the Solar System materials in galactic evolution and (2) unveiling the origin of the Solar System bodies to form planetesimals. To achieve these goals, a comet is the candidate target of NGSR. Since the surface materials of comets should have been processed by cyclic solar heating, space weathering, and cometary activity, NGSR will explore and sample not only the surface but also the subsurface materials, which should preserve the clues to primordial composition and formation process of the body. The nominal target of NGSR is Jupiter-family comet 289P/Blanpain, and the backup (short-term) targets are the E-type asteroid Nereus and the D-type asteroid 2001 SK162.
The NGSR spacecraft system consists of a Deep Space Orbital Transfer Vehicle (DS-OTV) to transport between Earth and the target body and a lander to sample the materials from there [2]. A concept study assumes its launch in early 2034, arrival at the target in 2040, and return of samples to Earth in late 2046. During the proximity phase, the global shape and geologic features of the target body will be observed using an optical navigation camera (ONC), and the size and volume will be determined using the ONC and a laser altimeter (LIDAR). The gravity or mass measurement will be performed by the LIDAR and radio tracking from ground. The surface thermophysical properties and composition will be derived using a thermal infrared imager (TIRI). Sampling sites will be determined using these data. A bullet/pneumatic type sampler on the lander will collect samples from the surface and the subsurface excavated by the impactor SCI, and a mass spectrometer on the lander will analyze volatile and organic matter from part of the samples. Most of the collected samples will be transferred to the reentry capsule on the DS-OTV every time after sampling. Probing the internal structure is another scope of this mission. Bistatic radar will probe the dielectric constant distribution of the interior. Small landing seismometer units deployed onto the surface will measure seismic waves activated by cometary activity or by the SCI impact. Furthermore, international collaboration is considered to improve the scientific significance of this mission, such as a near-infrared spectrometer with IAS, a dust detector with INAF, and a MASCOT-like small lander with DLR.
[1] e.g., Nakamura T. et al. (2022) Science, 90, eabn8671.
[2] Saiki T. et al., (2025) Acta Astronaut., 235, 120-128.
How to cite: Okada, T. and the NGSR Science Working Group: Next Generation Small-body Sample Return (NGSR): A Future Japanese Mission to a Comet, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10484, https://doi.org/10.5194/egusphere-egu26-10484, 2026.
Dark asteroids with featureless neutral to red spectra in the main asteroid belt are of particular interest due to their ability to potentially harbour primitive hydrated, and possibly organic-rich material. These asteroids belong to the spectroscopic C-complex, to the X-types with low geometric visible albedo values as well as to the T- and D-type end members of the Bus─DeMeo spectroscopic taxonomy, and most likely originate from heliocentric distances beyond Jupiter's orbit. Though there are previously identified asteroid families belonging to the C- and X-complex in the main asteroid belt, there are none belonging to T- or D-type. We used Gaia Data Release 3 visible reflectance spectra to study the average spectral profiles of the C- and X-complex asteroid families in the central and outer main belt (orbital semimajor axis between 2.5-3.7 au). We found that eight of these families, namely 96 Aegle, 627 Charis, 1484 Postrema and 5438 Lorre, previously classified as C-complex families, and 322 Phaeo, 1303 Luthera, 5567 Durisen and 53546 2000BY6 previously classified as X-complex families, have redder slopes than implied by their previous classification and could be better classified as T-/D-type families. Some of these families may also feed the near-Earth asteroid population, being responsible for the observed T-/D-type excess. However, the analysis of their principal components of Gaia Data Release 3 spectra suggest that further near-infrared observations are needed in order to verify this identification.
How to cite: Bhat, U., Avdellidou, C., Delbo, M., and Dyer, T.: Searching for primitive, dark, spectrally red asteroid families in the main belt with Gaia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10988, https://doi.org/10.5194/egusphere-egu26-10988, 2026.
Terrestrial planets are located in the inner region of the solar system, where the temperature was too high for water and highly volatile elements to condense. Nevertheless, the Earth contains a sufficient amount to harbor life, but the origin is still debated (carbon-rich meteorites, comets, enstatite chondrites [1-4]). The Hayabusa2 spacecraft (JAXA) collected samples from the C-type asteroid (162173) Ryugu, providing a unique opportunity to improve our knowledge on the origin and distribution of volatile elements. Recent studies on Ryugu and Bennu samples (OSIRIS-REx, NASA) revealed strong similarities with CI-type chondrites [5-9]. A recent study by [7] reported noble gas measurements on three Ryugu samples and revealed, for the C0209 sample, an extreme enrichment in Xe compared to other cosmochemical components accompanied by a strong mass-dependent fractionation of unprecedented magnitude (39.2 ‰/amu) in favor of the heavy isotopes relative to the light ones (Xe-X (P7)).
We measured the elemental and isotopic composition of noble gases, released by laser heating steps, of two among the six attributed samples of asteroid Ryugu from Chamber A : A0527 (0.8 mg) and A0532 (0.7 mg), with the aim to check the presence of the new Xe component [7], in order to understand if it is unique to sample C0209 or common in pristine C-rich material.
The xenon isotopic composition displays a mixture dominated by Xe-Q [10] plus solar wind and Xe-HL, with no evidence for the presence of Xe-X [7]. Xe-HL typically displays a balanced excess (from the p- and r-process) in light and heavy xenon isotopes relative to the Q phase. Interestingly, in these samples, there is a depletion in light xenon isotopes and an excess in heavy isotopes relative to Q. The excess cannot be purely attributed to fission, requiring contribution from the r-process. The depletion in light Xe isotopes cannot be explained by an atmospheric contamination. Such results induce an imbalance of p- and r-process in primitive asteroid material [5-9] and a heterogeneity in the spatial distribution of presolar component in the solar system or that the light xenon isotopic composition of the phase Q was overestimated in the past. The fact that the results do not show evidence for a contribution from the Xe-X component indicates a possible heterogeneity in terms of noble gas abundance and isotopic composition. Measurements of four other samples from Chamber A are ongoing.
[1] Marty 2012. EPSL 313-314:56-66. [2] Marty et al. 2016. EPSL 441:91–102. [3] Marty et al. 2017. Science 356:1069-1072. [4] Piani et al. 2020. Science. 369:1110-1113. [5] Okazaki et al. 2022. Science 379, eabo0431. [6] Broadley et al. 2023. GCA. 345:62-74. [7] Verchovsky et al. 2024. Nat. Comm. 15:8075. [8] Barnes et al. 2025. Nat. Astro. [9] Marty et al. 2025. MAPS. [10] Busemann et al. 2000. MAPS 35:949-973
This work was financially supported by CNES (project Hayabugaz) and received funding received funding from the European Research Council (ERC) under the European Union’s Horizon Europe Research and Innovation Program (Grant Agreement 101041122 to Guillaume Avice).
How to cite: Vayrac, F., Avice, G., and Marrocchi, Y.: New noble gas measurements of samples from asteroid Ryugu, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11047, https://doi.org/10.5194/egusphere-egu26-11047, 2026.
JAXA's Martian Moon eXploration (MMX) sample return mission aims to solve the long-debated origin of Martian moons Phobos and Deimos [1].This will be the first attempt to sample an object that either formed in the outer solar system and implanted [2,3,4] into the terrestrial planet region by a major dynamical process (the first origin scenario); or formed from a large impact and subsequently accumulated material from two, very possibly compositionally different, bodies, i.e. Mars and the impactor (the second scenario). In either scenario, impact processes by asteroids, meteoroids as well as Martian eject have altered the surfaces of the Martian moons and require investigation to study several aspects such as the crater formation and exposure of fresh sub-surface material, the comminution of surface boulders and regolith production, and the delivery of exogenous materials. To provide a frame for the MMX data interpretation, a laboratory experimental campaign is proposed simulating the impact processes on Phobos. We will present the results of our laboratory investigation of impact experiments using Phobos simulant materials at the Impact Lab of the University of Kent.
Acknowledgements: We acknowledge CNES and STFC funding for initiating this work.
References:
- Usui et al. Space Science Reviews 216, Issue 4, article id.49 (2020).
- Levison et al. Nature 460, Issue 7253, pp. 364-366 (2009).
- Vokrouhlicky, Bottke, Nesvorny. The Astronomical Journal 152, Issue 2, article id. 39, 20 pp. (2016).
- Kegerreis et al. Icarus, Volume 425, id.116337 (2025).
How to cite: Avdellidou, C. and Spathis, V. and the Kent Impact Lab team: Impact studies on Phobos simulant materials, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7027, https://doi.org/10.5194/egusphere-egu26-7027, 2026.
The upcoming JAXA Martian Moons eXploration (MMX) mission aims to clarify key unknows about Phobos and Deimos and reveal the long-debated origin of Mars’ moons. The MMX Infra-Red Spectrometer (MIRS) will help to determine the surface structure, composition and mineralogy of Phobos. Through these and other observations, MMX represents the valuable opportunity to increase knowledge on small bodies, Mars and the early Solar System.
The aim of the European Space Agency’s Vulcan Analogue Sample Facility is to support and de-risk exploratory missions through simulant research and testing, and is the driving force for this project. The incorporation of several European instruments onboard MMX, including the CNES-led MIRS, provides further motivation.
Several Phobos simulants produced by academic and commercial groups have been utilized throughout the preparatory stages of the mission, including UTPS, OPPS and PCA/PGA [1,2,3]. However, gaps remain in the properties represented and there is yet to be a simulant which represents the spectral profile of the moon in full. Phobos is a spectrally dark and largely featureless body, although it has regions which differ in the spectral slope. Most of the surface is the steeply sloped red unit, except for the area around Stickney Crater, which is a flatter blue unit [4]. As most existing Phobos simulants are global, they also do not demonstrate the slope variation on the surface.
At the Vulcan Facility, six preliminary simulants were created to assess the available candidate materials in their suitability in representing Phobos regolith in the near infrared, compared to observational data from orbiters. The core aim with these simulants was to display the spectral features present (~0.65µm and 2.7µm) and represent the mineralogy. The results from these are being used to develop an improved, more representative simulant following the initial design. Beyond this more general simulant, the goal of this work is to produce individual simulants for the red and blue units of Phobos’ surface.
References: [1] Miyamoto et al., 2021. Earth Planets and Space, 73:1 [2] Wargnier et al., 2023. Monthly Notices of the Royal Astronomical Society, 524:3 [3] Landsman et al., 2021. Advances in Space Research 67:10. [4] Fraeman et al., 2014. Icarus, 229.
How to cite: Vosper, D., Martin, M., and Manick, K.: Towards Representative Infrared Phobos Simulants: Design, Iteration, and Evaluation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18138, https://doi.org/10.5194/egusphere-egu26-18138, 2026.
Hera is the ESA’s contribution to an international collaboration project named Asteroid Impact and Deflection Assessment (AIDA). Last 26th September 2022, NASA’s DART mission performed a kinetic impact on Dimorphos, the Didymos secondary asteroid. At the end of 2026, Hera will arrive at the binary system, following up for a detailed post-impact survey, to fully characterize this planetary defense technique. In addition, Hera will deploy two CubeSats, Juventas and Milani, which will contribute to asteroid science. In March 2025, Hera performed a Mars flyby, during which Earth-based radiometric data and optical images of the planet and its moons, Phobos and Deimos, were acquired. This flyby provided a valuable opportunity to test and validate Optical Navigation (OPNAV) image-processing pipelines and orbit determination algorithms and tools developed within the Hera mission.
In this context, optical measurements derived from Hera Asteroid Framing Camera (AFC) images of Deimos and Phobos allow the extraction of surface normal points, which can be used to refine the moons’ ephemerides. Images of Mars, on the other hand, are primarily exploited for optical navigation purposes: limb and center-of-figure measurements provide angular constraints on the spacecraft–planet geometry, contributing to the improvement of the spacecraft’s trajectory estimation during the flyby.
This work presents an OPNAV image-processing pipeline developed for the Hera mission. The pipeline begins with the calibration of the Hera’s AFCs using star-field images, allowing the estimation of the optical distortion parameters of both cameras. The subsequent processing focuses on the extraction of Phobos and Deimos center-of-figure from the acquired images of the Mars flyby. For both calibration and centroid extraction, we use the ARAGO software, developed at the Observatoire de Paris, to find star centroids and then determine the moons’ astrometric points. Finally, these OPNAV measurements are then incorporated into the orbit determination process to assess their impact on the spacecraft trajectory estimation. Preliminary results are presented to demonstrate the performance of the proposed approach.
How to cite: Banzi, D., Lasagni Manghi, R., Zannoni, M., Gramigna, E., Tortora, P., and Lainey, V.: Optical Navigation Image Processing and Orbit Determination for Hera’s Mars Flyby , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20537, https://doi.org/10.5194/egusphere-egu26-20537, 2026.
The primary goal of this work is to investigate the properties of the inner coma of comets and establish connections between the processes occurring within it and specific locations on the surface and subsurface of the comet. The analysis of gas and dust in the inner coma and their connection with the surface of comets is crucial to understand the context of cometary activity and represents an important reference for the ESA and JAXA missions as Comet Interceptor and for small bodies showing ''cometary activity''. Those efforts rely on the capability to model and forecast the activity of comets, which in turn relies on connecting observed activity to surface properties and regions.The work is developed in two parts:
- Our first focus is the analysis of the dust and gas coma of comet 67P using data acquired by the ESA Rosetta mission during the period between July and November 2015, when activity was near its peak postperihelion.
- The second focus is the development of a Lagrangian code based on the Smoothed Particle Hydrodynamics (SPH) method to investigate transient phenomena, such as volatile and refractory emissions from the surface (M. Teodori et al. 2024, 2025).
The Visible InfraRed the Thermal Imaging Spectrometer (VIRTIS) and the ALICE ultraviolet spectrograph, observed and detected a series of outbursts and jets (Rinaldi et al. 2018, Noonan et al. 2021). H2O, CO2, and O2 were all indirectly observed by ALICE within outbursts via emission fingerprints of dissociative electron impact from the daughter products H, C, and O, identified in the spectra as the first two members of the H I Lyman series, OI multiplets at 1152, 1304, and 1356 Å, and weak multiplets of C I at 1561 and 1657 Å . VIRTIS detected and characterized the dust properties of the jets and outburst in terms of radial profile, light curve, color, and dust mass loss in the VIS and IR wavelength range. The outburst observations show that mixed gas and dust outbursts can have different spectral signatures representative of their initiating mechanisms, with outburst showing indicators of a cliff collapse origin or showing fresh volatiles being exposed via a deepening fracture. Preliminary analysis shows the cometary activity observed after some outburst events has a moderate CO2/H2O ratio, while others show only a large increase in reflected light due to dust. When connected to specific surface regions and provided with the proper spectral signal, this analysis opens up the possibility of remote spectral classification of cometary activities with future work.The second focus of this work is to consider the physical processes driving the comet activity. We aim at simulating gas and dust emission from a surface fracture, by introducing an advanced numerical model that adopts the Smoothed Particle Hydrodynamics (SPH) approach. The code accounts for multiple components and incorporates several physical mechanisms. Among them, phase transitions (mainly sublimation and deposition), viscous dynamical interaction between gas and solid components (dust and eventually icy grains), solar radiation, and volatile-surface dynamical and thermal interactions. Preliminary results will be presented during this session.
How to cite: Rinaldi, G., Noonan, J., Teodori, M., Maggioni, L., and Formisano, M.: Analysis of Dust and Gas emission at 67P/Churyumov-Gerasimenko, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20540, https://doi.org/10.5194/egusphere-egu26-20540, 2026.
The Rapid Apophis Mission for Space Safety (RAMSES) is an ESA’s mission to study the near-Earth asteroid 99942 Apophis before, during and after its close encounter with the Earth on April 13, 2029. Given the very small closest approach distance, strong tidal forces may induce significant changes in Apophis’s rotational state, surface morphology, and internal structure. This event offers a unique opportunity to observe and quantify these effects, advancing our understanding of rubble-pile asteroids’ formation and evolution.
In this regard, a detailed reconstruction of Apophis’ internal structure will be crucial to characterize the internal alterations induced by Earth’s strong gravitational pull during the flyby, giving important information about the asteroid’s internal cohesion and evolution history.
Among the different payloads and experiments currently foreseen, the Radio Science Experiment (RSE) will allow to estimate the asteroid’s gravity field, rotational state, and heliocentric orbit through the precise orbit determination of the RAMSES spacecraft and two CubeSats that will be released before the Apophis closest approach. The gravity field can be employed in the so-called Gravity Inversion (GI) problem, i.e. the process aimed at inferring the internal structure of the body starting from its gravitational field. A wide variety of techniques have been proposed and employed to address the GI problem. For example, global GI relies on the inversion of the direct problem, which links the density distributions with the generalized moments of inertia. This approach yields continuous density distributions that exactly reproduce the observed gravitational field, but suffers from an infinite number of possible solutions. Alternatively, the Markov Chain Monte Carlo (MCMC) algorithm is a novel approach that allows to estimate the size and density of pre-defined regions within the body’s volume starting from its gravitational field. This technique proved to be very versatile since it has been used for large, differentiated bodies, such as Vesta, and smaller rubble piles like Bennu.
This work describes the gravity inversion methodologies currently under development in preparation for the RAMSES mission. Particular focus is placed on the MCMC techniques, given their flexibility and capability of integrating multiple data types beyond gravity, leading to a more comprehensive analysis.
How to cite: Scalera, F., Zannoni, M., Lasagni Manghi, R., Gramigna, E., and Tortora, P.: Small bodies interior characterization through gravity inversion in preparation for ESA’s RAMSES mission to asteroid Apophis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20635, https://doi.org/10.5194/egusphere-egu26-20635, 2026.
Cosmic dust grains in the Solar System acquire a charge through several processes of which the main are plasma collection, secondary electron emission and photoionisation. The equilibrium charge attained depends on the local space environment, which varies both temporally and spatially, as well as on the size and composition of the dust grain. Consequently, the charging time determines whether the equilibrium charge can be achieved. Dust grain charging is relevant because it influences the trajectories of dust grains moving through the time-dependent solar magnetic field. This talk briefly reviews the charging mechanisms, assumptions of the charging simulations and gives an overview of plasma and charging properties in the heliosphere, and its variations in space and in time.
How to cite: Arnet, T. and Sterken, V.: An inventory of dust charging in the heliosphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1957, https://doi.org/10.5194/egusphere-egu26-1957, 2026.
Enstatite chondrites (ECs) exhibit isotopic compositions closely align with the Earth, rendering them indispensable reference for deciphering the building blocks of our planet. Impactors with ECs-like compositions, key contributors to proto-Earth, were proposed to have underwent differentiation. However, such differentiation poses a formidable challenge given the small size of these impactors and the lack of gravity-driven permeable flow, and the high melting temperature of enstatite. Here, we present high-pressure melting experiments on EH3 chondrite, complemented by three-dimensional X-ray computerized tomography analyses of metal segregation under various conditions. Thermodynamic simulations on the temperature evolution of EH chondrite-like embryos reveal that heat produced by radioactive decay systems (26Al, 60Fe and 40K) is sufficient to melt more than 20% of the silicate components, thus driving metal-silicate segregation only if these embryos accreted early (within 1.1 Myr post-CAI). Such embryos could have attained sizes comparable to the Moon. In contrast, the parent bodies of EH chondrites formed relatively late (1.88–2.0 Myr post-CAI), with radii between 125 and 170 km. Our findings provide pivotal insights into the accretion timing, differentiation mechanisms, and structural characteristics of EH chondrite-like embryos in the early Solar System, addressing a long-standing gap in our understanding of terrestrial planet formation.
How to cite: Du, W. and Li, Q.: Rapid accretion of enstatite chondrite (EH)-like embryo as impactors for the proto-Earth, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15339, https://doi.org/10.5194/egusphere-egu26-15339, 2026.
Destiny+ is a Japanese-German space mission to be launched in 2028, first flying by the near Earth Asteroid Apophis in 2029 after which it will continue on its route to the active asteroid Phaeton for a flyby in 2030. The period around 2029-2030 is in the phase of the solar cycle in which small interstellar dust and cometary dust is focused near the ecliptic plane. This presents unique and ideal conditions for in situ measurements of interstellar dust in the solar system, close to the Earth. We present predictions for the interstellar dust flux and flow direction that Desiny+ will be able to measure for different assumed material properties. We use two prediction methods of which one is designed to take into account the filtering in the heliosheath using previous in situ measurements.
How to cite: Jestin, T., Hunziker, S., Strubb, P., Krüger, H., Moragas-Klostermeyer, G., Srama, R., Janisch, T., and Sterken, V.: Interstellar dust predictions for the Destiny+ mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21022, https://doi.org/10.5194/egusphere-egu26-21022, 2026.
Posters virtual: Mon, 4 May, 14:00–18:00 | vPoster spot 4
EGU26-11477 | ECS | Posters virtual | VPS27
A Petrographic and Micro-Analytical Framework for the Study and Classification of MeteoritesMon, 04 May, 14:33–14:36 (CEST) vPoster spot 4
This contribution presents a petrographic, microstructural, and micro-analytical approach developed for the comprehensive study of ordinary chondrites, as part of a master’s thesis aimed at defining an analytical protocol for the petrological and minerochemical characterization of extraterrestrial materials. The ultimate goal is the establishment of a dedicated laboratory for the petrological study of meteorites, exploiting available instrumentation and acquired micro-analytical expertise to achieve both a complete classification of chondrites and a deeper understanding of the processes governing their genesis and evolution.
The study was carried out in collaboration with the Italian Museum of Planetary Sciences, where an internship allowed the examination of a reference collection of classified meteorite thin sections commonly used for educational purposes. Subsequently, three ordinary unclassified chondrites, provided by the “Museo del Cielo e della Terra” (San Giovanni in Persiceto, Bologna, Italy) and by a private collection, were investigated.
The analytical workflow includes: (i) macroscopic measurements and photographic documentation; (ii) petrographic analysis by transmitted and reflected light optical microscopy for microstructural and mineralogical characterization; (iii) SEM-EDS X-ray compositional mapping on the whole petrographic thin section as well as on selected chondrules and microstructural sites; (iv) SEM-EDS quantitative microanalyses of mineral phases; and (v) micro-Raman spectroscopy.
Preliminary results indicate that, from a chemical perspective, two of the unclassified samples can be assigned to the H group and one to the L group of ordinary chondrites. Petrographic observations classify the investigated meteorites as petrologic types 4 to 6. The most common chondrule textures observed include porphyritic and barred olivine, porphyritic olivine–pyroxene, granular olivine–pyroxene, radial pyroxene, and complex chondrules.
SEM-EDS compositional maps of entire thin sections and selected microstructural domains enable visualization of textural relationships, estimation of modal mineral abundances relative to metallic phases, and the development of a comparative framework among ordinary chondrites. Mineral chemistry data are compared with literature values to refine classification criteria. Micro-Raman spectroscopy is performed on opaque phases or on selected minerals for the correct identification of the polymorphic phase which constrains proper ranges of P-T conditions. Moreover, micro-Raman analyses are employed to characterize solid and fluid/melt inclusions within primary minerals, assess surface alteration features, and investigate dust extracted from fractures, providing insights into secondary processes related to atmospheric entry and post-impact evolution.
How to cite: Borghetti, S., Di Martino, M., Ferrando, S., Faggi, D., Ghignone, S., Morelli, M., Serra, R., and Vaggelli, G.: A Petrographic and Micro-Analytical Framework for the Study and Classification of Meteorites, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11477, https://doi.org/10.5194/egusphere-egu26-11477, 2026.
EGU26-21015 | Posters virtual | VPS27
Deciphering mixtures of complex organic compounds in cosmic dust particles using JAXA's Destiny+ Dust AnalyzerMon, 04 May, 14:36–14:39 (CEST) vPoster spot 4
Organic compounds are a ubiquitous component of cosmic dust and provide insight into the origin of planetary systems, the availability of carbon for life in the solar system and beyond, and the distribution of potential biosignatures in the universe. Compositional and dynamical analysis of such dust grains can shed insight into their origin. The Destiny Dust Analyzer (DDA) onboard JAXA’s interplanetary space mission DESTINY+ will detect and analyse the composition of (sub-)micron sized dust ejecta during flybys of asteroids Apophis and Phaethon [1,2]. DDA will characterise both interplanetary and interstellar dust grains during the mission’s lifetime [3]. DDA is an impact ionisation time-of-flight mass spectrometer, whereby dust particles incident onto the instrument’s target at hypervelocity (≥ 2 km s-1) vaporise and partially fragment into various constituent ions and neutrals. Here, we investigate the capability of DDA to detect a mixture of complex organic compounds in single cosmic dust particles. An organic cosmic dust analogue is prepared by coating polycyclic aromatic hydrocarbon, perylene (C20H12), microparticles with an ultrathin overlayer of a conductive polymer, polypyrrole H(C4H2NH)nH, to enable acceleration up to hypervelocities with a high-voltage van de Graaff instrument. Time-of-flight mass spectra obtained at impact speeds ~3-20 km/s are recorded in this calibration campaign. The characteristic parent molecular ion for perylene, [C20H12 (+H)]+, is observed at m/z 251 ± 1 in mass spectra arising from impacts between 3 and 8 km s-1. However, between 8 and 18 km s-1, no such parent ion is observed. Instead, impact ionisation mass spectra exhibit a characteristic series of homologous [CnHm]+ fragments originating from both polypyrrole and perylene, alongside some non-sequential ions which may be diagnostic for distinguishing between different organic components in cosmic dust. The contributions of each species to fragmentation patterns in the mass spectra is coupled with the impact velocity. Our results are in agreement with Mikula et al. (2024), who investigated impact ionisation of polypyyrole-coated anthracene particles for the Interstellar Dust EXperiment (IDEX) onboard NASA's Interstellar Mapping and Acceleration Probe (IMAP), and observed a similar relationship between fragmentation pattern and velocity [4].
Additional experiments with a range of PAHs, heterocycles, and lower mass organics at various velocities, will yield further insight into the detection and characterisation of heterogeneous dust likely to be encountered by DDA. Similarly, theoretical chemical calculations could assist in deciphering the contribution of different species to mass spectral features via the analysis of dissociation thermodynamics and kinetics.
[1] Ozaki et al. (2022) https://doi.org/10.1016/j.actaastro.2022.03.029
[2] Simolka et al. (2024) https://doi.org/10.1098/rsta.2023.0199
[3] Krüger et al. (2024) https://doi.org/10.1016/j.pss.2024.106010
[4] Mikula et al. (2024) https://doi.org/10.1021/acsearthspacechem.3c00353
How to cite: Khawaja, N., Srama, R., Chan, D. H. H., Simolka, J., Armes, S. P., Mikula, R., Hirai, T., Li, Y., Strack, H., O'Sullivan, T. R., Bera, P. P., Mocker, A., Trieloff, M., Postberg, F., Hillier, J. K., Kempf, S., Sternovsky, Z., Yabuta, H., and Krüger, H.: Deciphering mixtures of complex organic compounds in cosmic dust particles using JAXA's Destiny+ Dust Analyzer, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21015, https://doi.org/10.5194/egusphere-egu26-21015, 2026.
